Because people don't know how to act.
I've been on a consulting contract for the last 8 months with this company. About a month ago, I was notified that they would not be renewing the contract (the company is going into re-org, there's no adequate role for me, and I'm very expensive as a contractor), and that my last day would be March 31. Subsequently, two weeks ago, I was given formal notice of contract ending, per agreed upon contract terms.
So the last two weeks, I've continued to engage as much a possible, to try to remain active on my way out. But people have acted so strangely. When they found out I was leaving at the end of the month, they started literally ignoring my presence in the office.
Now I would expect that people would stop giving me new work to do, etc. But literally, people started ignoring the fact that I was even there. I would walk through the room, and no one would acknowledge my presence. No hello, no smiles, even their eyes would not fall upon me. It was the oddest feeling. I felt like I was invisible.
So I decided not to go in any longer. I'm fine with the contract ending and wanted to try to remain productive through my last day since they were paying me for it, but people just got so weird about it all, I decided to stop going in. And quite frankly, I feel better for it. It gave me such a strange feeling to be treated that way. I decided not to subject myself to it any longer.
Onward and upward...to the next chapter....starting tomorrow...whatever it is....